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Use when input is read into an array and then accessed with arithmetic operations to form values
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基于 SOC 职业分类
| name | avoid-array-indexing-arithmetic |
| description | Use when input is read into an array and then accessed with arithmetic operations to form values |
A KLEE-coverage code transformation. Applying it rewrites C source so symbolic execution explores more of the program's behavior.
When input is read into an array and then accessed with arithmetic operations to form values
Read input as a single integer and extract components using division and modulo operations
Array indexing with arithmetic creates complex symbolic expressions that are harder for KLEE to reason about, while integer arithmetic operations produce simpler constraints
Before:
#include <stdio.h>
int arr[4];
int main(){
for(int i=0;i<4;i++) scanf("%1d",arr+i);
int a=arr[0]*10+arr[1], b=arr[2]*10+arr[3];
int s=0;
if(a<=12&&a>0) s++;
if(b<=12&&b>0) s+=2;
if(s==0) printf("NA");
else if(s==3) printf("AMBIGUOUS");
else if(s==1) printf("MMYY");
else printf("YYMM");
}
After:
#include<stdio.h>
int main()
{
int a, b, c, d, e;
scanf("%d", &e);
a=e/100;
b=e-100*a;
if(a>=1&&a<=12)
{
if(b>=1&&b<=12)
printf("AMBIGUOUS");
else
printf("MMYY");
}
else
{
if(b>=1&&b<=12)
printf("YYMM");
else
printf("NA");
}
}
8d2c1bd2Use when printf statements output strings without trailing newlines
Use when array is accessed with direct user input as index (0-based indexing)
Use when the program accesses a precomputed table using an offset (e.g., arr[n-1]) that introduces an arithmetic operation between the symbolic input and the index
Use when loop variables iterate over character values (e.g., ASCII codes) to represent different operations or choices
Use when code uses a loop to search for an input value in an array and then uses the found index for further computation
Use when code reads a fixed number of characters into an array and only accesses individual elements